 /*******************************************************************************
  * Copyright (c) 2000, 2006 IBM Corporation and others.
  * All rights reserved. This program and the accompanying materials
  * are made available under the terms of the Eclipse Public License v1.0
  * which accompanies this distribution, and is available at
  * http://www.eclipse.org/legal/epl-v10.html
  *
  * Contributors:
  * IBM Corporation - initial API and implementation
  *******************************************************************************/
 package org.eclipse.ui.internal.navigator.resources.actions;

 import java.util.ArrayList ;
 import java.util.Iterator ;
 import java.util.List ;

 import org.eclipse.core.resources.IResource;
 import org.eclipse.core.runtime.IAdaptable;
 import org.eclipse.jface.viewers.IStructuredSelection;
 import org.eclipse.jface.viewers.StructuredSelection;

 /**
  * Provides utilities for checking the validity of selections.
  * <p>
  * This class provides static methods only; it is not intended to be instantiated
  * or subclassed.
  * @since 2.0
  * </p>
  */
 public class ResourceSelectionUtil {
     /* (non-Javadoc)
      * Private constructor to block instantiation.
      */
     private ResourceSelectionUtil() {
     }

     /**
      * Returns whether the types of the resources in the given selection are among
      * the specified resource types.
      *
      * @param selection the selection
      * @param resourceMask resource mask formed by bitwise OR of resource type
      * constants (defined on <code>IResource</code>)
      * @return <code>true</code> if all selected elements are resources of the right
      * type, and <code>false</code> if at least one element is either a resource
      * of some other type or a non-resource
      * @see IResource#getType()
      */
     public static boolean allResourcesAreOfType(IStructuredSelection selection,
             int resourceMask) {
         Iterator resources = selection.iterator();
         while (resources.hasNext()) {
             Object next = resources.next();
             if (!(next instanceof IResource)) {
                 return false;
             }
             if (!resourceIsType((IResource) next, resourceMask)) {
                 return false;
             }
         }
         return true;
     }

     /**
      * Returns the selection adapted to IResource. Returns null
      * if any of the entries are not adaptable.
      *
      * @param selection the selection
      * @param resourceMask resource mask formed by bitwise OR of resource type
      * constants (defined on <code>IResource</code>)
      * @return IStructuredSelection or null if any of the entries are not adaptable.
      * @see IResource#getType()
      */
     public static IStructuredSelection allResources(
             IStructuredSelection selection, int resourceMask) {
         Iterator adaptables = selection.iterator();
         List result = new ArrayList ();
         while (adaptables.hasNext()) {
             Object next = adaptables.next();
             if (next instanceof IAdaptable) {
                 Object resource = ((IAdaptable) next)
                         .getAdapter(IResource.class);
                 if (resource == null) {
                     return null;
                 } else if (resourceIsType((IResource) resource, resourceMask)) {
                     result.add(resource);
                 }
             } else {
                 return null;
             }
         }
         return new StructuredSelection(result);

     }

     /**
      * Returns whether the type of the given resource is among the specified
      * resource types.
      *
      * @param resource the resource
      * @param resourceMask resource mask formed by bitwise OR of resource type
      * constants (defined on <code>IResource</code>)
      * @return <code>true</code> if the resources has a matching type, and
      * <code>false</code> otherwise
      * @see IResource#getType()
      */
     public static boolean resourceIsType(IResource resource, int resourceMask) {
         return (resource.getType() & resourceMask) != 0;
     }

 }

